Bladed stator or rotor constructions with means to supply a fluid internally of the blades



Jan. 12, 1960 A. A. LOMBARD 2,920,865

BLADED STATOR OR ROTOR CONSTRUCTIONS WITH MEANS TO SUPPLY A FLUIDINTERNALLY 0F Filed on. 2631953 THE BLADES 5 Sheets-Sheet l Jan. 12,1960 A. A. LOMBARD 2,920,865

BLADED STATOR 0 ROTOR CONSTRUCTIONS WITH MEANS TO SUPPLY A FLUIDINTERNALLY OF THE BLADES Filed Oct. 26, 1953 5 Sheets-Sheet 2 Jan. 12,1960 A. A. LOMBARD BLADED STATOR OR ROTOR CONSTRUCTIONS WITH MEA TOSUPPLY A FLUID INTERNALLY OF THE BLADES Filed Oct. 26, 1953 3Sheets-Sheet 3 United States Patent BLADEDSTATOR OR ROTOR CONSTRUCTIONSWITH MEANS TO. SUPPLY A FLUID IN'IZER- NALLY OF THE BLADES Claimspriority,,application Great Britain October 31-, 1952 8= Claims. (Cl.253-39-15) Thisv invention relates; to-bladed stator and rotorconstructions for fluid machines, for instance, for axial flow turbinesor compressors, which constructions employ blades supported in a, drumor disc structure by attachment portions on the-blades, which attachmentportions have shoulders engaging correspondinglyw shouldered slots inthe disc or drum, and which attachment portionsaiford between themtunnels extending across the drum or disc and suitable to convey aflowof fluid between the blade attachment portions. Such a bladedconstruction will be referred tohereinafter as a bladed construction ofthe kind specified.

Itv is known to. supply. a.fluid, suchas compressed: air, totheinteriors of bladesfor thepurpose of cooling or beating them duringoperationv of the fluid machine of which they form part and thisinvention is further concernedwith bladed constructionsof the kindspecified in,

which the blades have-internalpassagesto convey a heating orcoolingfluid.

According to.the..present invention, a bladed constructionof the kindspecified comprises a. plurality of blades each having at least an inletlengthwise passage therein.

and a deliverylengthwise-passage therein, which, passages areinterconnected at their. ends remote fromtheiattachment. portionof. theblade, and,which passages, extend through the attachment portion to openinto-thetunnels on opposite sides of thev attachment portion, each bladebeing arranged so that its v inlet passage opens into the same tunnel asthe inlet, passage of the next adjacentblade on one side of it andsothatits delivery passage opens into the sametunnel. as-thedelivery, passageof the .next

adjacent blade on the other. side of it,.and.blanking means,

toclose-ofl atleast thetcorresponding ends of alternate tunnels andtheopposite endsof the remaining tunnels.

, With the arrangement ofthis invention, the said alternatetunnels-formed between blades of a row of blades may be employedv toconvey asupplyof a fluid, say, com-..

In one preferred construction as applied to a bladed 1' rotorconstruction with the blades-supportedat theperiphery ofaav rotorstructure, the tunnels into which the inlet passages: opten, areblanked-E fromthe downstream side of the blade attachment portions, and:a pressure fluid which-is conveniently compressed-air issupplied on theupstream side ofthe: blade: attachmentaportions, andtherpressurefluidflows fromthis space: into the tunnels andithen throughthe inlet and: delivery passages in the blades; into the. remainingtunnels which are blanked-off from-the upstream side of the. bladeattachmentportions: so. that thefipressure fluid exhausting from thebladesflows intotheispace on. the downstream side of thebladerattachmentportions;

In: another preferred construction as appliedato; a "bladedirotorconstruction, the tunnelsinto which the inlet passages open, areblanked-oh at each end, and the tun- 2,920,865 Patented Jan. 12, 1960blades form a, complete annular shroud, a shouldered rootfixingportionby whichthe bladeis engaged with-the rotor disc or, drum, and a.circumterentially-narrow, axially-extensive stem which joins theplatform to the root fixing, portion, so-that spaces of substantialdimen sions a form d between the p rsv o a j t em and these spacesare,conveniently. used as the tunnels,

Two embodiments f this, invention will now be described asappliedtoturbinerotor constructions, the description making reference to,theaccompanying drawings, in which Figure 1 is a form, of blade suitablefor use in the turbine constructions,

Figure 2 is ,a. sectionlonthe line 2 2 of Figure 1,

Figure 3 is a view corresponding to part of. Figure 1 showing the rootend of a blade such as-is assembled next to the bladeofqFigure 1,

Figure 4, is a section ontheline 44 of Figure 1, drawn Ito-alargerscale,

Figured be View similar to Figure 4 of a modified type of. blade, IFigure6 is a perspective, view. of p art of one turbine rotorconstructionusing the blade-S illustratedin Figures 1. to 4, the Viewbeing from the upstream side of the rotor,

Figure-J is an axial view on part of the turbine rotor of u ei mmhe-downs te my d i Figure 8 is. an axial, view of the upstream side of asecond on truction,

Figure 9 isa sectionon the line 9-9- of Figure 8, and

Figure. 1.0, is a. section. on th 1ine.10.10 of Figure 9.

In,t efirstembgdim ti i s Q 4 nd d the invention applied tothe' ro'tor,of an axialrflow turbine of, a, gas=turbine engine, which rotorcomprises a. rotor disc. sarryi e t s Pe ip ery. wine f individual blaelements each of which comprises a vane portion 11 pon hicht e orkiuid,- ft e e mp n es sra ial r nner endan at ac m n P r ion,

In this construction the attachment portion comprises (Figuresl to4)three essential parts, abladeplatforrn 12 from which the vane 11of'the-blade projects, a root fixing portion 13 for retainingthe bladein position on the rotor disc, structure, which root fixing portion (13)has a number of outwardly-facing shoulders 13a in its circumfierentiallyedirected. faces and which engages in a slot having.complementary shoulders and cut in a thickened periphery 10a or" therotor disc 10, and a stem portion 14 which is. in.,,the form of acircumferentially-narrow, axially-.extensiyeweb so. as to have a pair ofcircumferentiallyrfacing surfaces 14a and which thus has a gen- .erallynarrower cross section than either the platform 12 or the root fixingportion 13 and interconnects; these parts. The platforms 12 of a ringofblades co-operate in circumferential abutment to form a substantiallycomplete annular shroud for the inner ends of the vanes 11 ofthe. ringof blades, and the. root attachmentportions 12,, 13,14 -form withtheportions 15 of the rotor disc 10 between the slots a, series of ductpassages (16.), referred to hereinafter as tunnel-like spaces 16, whichextend axially;- across. the periphery of the disc from theupstream sideof the disc to the downstream side.

The vane portion 11 of each blade in the ring of blades is formed withthree lengthwise passages 17, 1 8; 19,

.a pair of narrow webs 20 which extend across the thickness of the vaneportion from the convex surface thereof to the concave surface thereofand these webs 20 are partly removed to form a chamber as indicated at'22 in Figures 4 and 5 adjacent the tip of the blade, so

that the three passages 17, 18, 19 are interconnected adjacent the tipof the blade. The blade is provided with an outer shroud portion 21which may conveniently be formed as indicated in Figure 4 in one piecewith the vane 11 or as indicated in Figure 5 separately from the vane 11of the blade and brazed in position at the tip to close-off the passagesin a manner preventing leakage from them while permitting fluid to flowbetween them. In the former case the shroud portion 21 may Thelongitudinal passages 17, 18, 19 have extensions 17a, 18a, 19arespectively through the platform 12 of the blade, and the extensions ofthe passages in the leading and trailing edges of the vane portion openat their inner ends through one circumferentially-facing surface 14a ofthe stem 14 and the extension 19a of the mid chord passage 19 opens tothe other circumferentiallyfacing surface 14a of the stem 14. The bladesare divided into two sets, one of which sets comprises blades eachhaving their root attachment portions as shown in Figure 1 and havingits leading and trailing edge passage extensions 17a, 18a opening to theright of the stem 4 (as viewed axially from the upstream side of therotor),

and the other of which sets comprises blades having their rootattachment portions as shown in Figure 3 and I having their leading andtrailing edge passage extensions 17a, 18a opening to the left ofthe stem14. The blades are assembled in the disc 10 so that the blades of the Itwo sets alternate with one another and thus each blade 'has itsextensions 17a, 18a of the leading and trailing edge passages 17, 18opening into the same tunnel-like space 16 as the correspondingextensions of the next ad acent blade on one side, and has itsextensions 19a of the mid chord passage 19 opening into the sametunnel-like space as the corresponding extension 19a of V the mid-chordpassage 19 of the blade next adjacent it on its opposite side.

Blanking means is provided to blank-off one end of each tunnel-likespace 16. The blanking means is arranged so that the tunnel-like spaces16 are left open alternately to the upstream side and the downstreamside 'of the turbine disc .10, the tunnel-like spaces 16 into which theextensions 17a, 18a of the leading and trailmg edge passages 17, 18open, communicating with the upstream side of the turbine disc 10, andthe other tunnel- 'like spaces 16 opening to the downstream side of theturbine disc so that the mid chord passages 19 communicate with thedownstream side of the turbine disc 10.

The blanking means may comprise a series of plates fitted on to the rim10a of the disc 10 and bearing against the end surfaces of the stems 14.

Referring to Figure 6, the blanking means for the upstream surface isillustrated as comprising a number of plates 24 with cutaway portionsopposite the tunnels 16 which are to be left uncovered, and havingflanges along their outer edges to engage with undercut channels 25 inthe upstream edges of the blade platforms 12 and having along theradially inner edges flanges 26 to rest on a ledge-like projection 27from the disc periphery to locate the plate radially. The upstream endof each jecting from it and when the plates 24 are in position the loweredges of the cutaway portions engage behind the hooked features 28...

The blanking means for the downstream surface is shown (Figure 7) ,ascomprising a number of individual blanking plates 30 which engage bytheir radially outer edges in slots 31 (seen in Figures 1, 3 and 6) inthe downstream edges of the blade platforms 12 and which engage bylateral lugs 32 behind hooked features 33 projecting from the downstreamend of the root fixing portions 13 and by deformable tabs 34 at theirradially inner ends in a shallow annular channel 35 cut in the periphery10a of the disc 10.

Pressure air is supplied to the rotor disc 10 on its upstream side andthe pressure air flows into the tunnellike spaces 16 which are open tothe upstream side of the disc 10 and thence into and along thelengthwise inlet passages 17, 18 in the leading and trailing edges ofthe blades to the tips thereof, into and along the mid chord lengthwisedelivery passages 19 back to the root attachment ends of the blades,into the tunnel-like spaces 16 which communicate with the downstreamside of the disc and thence into the working fluid annulus of theturbine.

The pressure air supplied to the upstream side of the disc 10 may besealing air as is usually employed for preventing leakage of workingfluid radially inwards between the upstream edges of the blade platforms12 and the adjacent stationary structure (not shown). Usuallytheupstream edges of the platforms 12 and the adjacent stationarystructure are formed to provide a labyrinth seal at this point and thepressure air is suppliedto the space between the upstream side of theturbine disc 10 and the stationary structure from the compressor of thegas-turbine engine.

-It will be appreciated the compressed air is at its coolest 'in flowingalong the leading and trailing edge passages 17, 18 and so has itsgreatest cooling effect where it is most needed.

In a second embodiment (Figures 8-10) which is also applied to coolingthe blades of a turbine rotor of a gas-turbine engine, similar bladesare employed as those described in connection with the first embodiment.

In this construction, however, the tunnel-like spaces 16..between thestems 14 into which the passage extensions 17a, 18a of the leading andtrailing edge passages 17, 18 open, are blanked off from both theupstream and downstream sides of the disc 10 and are connected bypassages through the disc periphery 10a to a space 40 radially inwardsof the disc periphery 10a, which space 40 is within an annular axialflange 41 formed on the disc inwards of its periphery 10a and withinannular stationary structure 43. This flange 41 is formed externally asthe rotating member of a labyrinth seal to cooperate with stationarysealing members 42 carried by the stationary structure 43 locatedradially inwards of the labyrinth seal formed between the upstream edgesof the blade platforms and the adjacent stationary structure 52.

The spaces 16 into which open the leading and trailing edge passages 17,18, are connected with the space 40 by means of an annular channel 44cut in the periphery of the turbine disc 10 and extending radiallyoutwards to theportions 15 of the rotor disc between the bladeslots andby drillings 45 leading from the space 40 through the disc 10 to theradially inner end of the channel 44. Air is prevented from flowing fromthe channel 44 into the spaces 16 into which open the mid chord passages19 by means of blanking plates 46. The plates 46 thus occupy and fillthe parts of channel 44 where it divides alternate shouldered portions15 and each plate 46 has serrated edges to coincide with the shoulder onthe portion 15 and to co-operate with the shoulders on'the adjacent rootfixing portions 13. Each plate 46 also has'a tsaapeaneae 46a overlyingthe portion 15 to prevent it falling tothebottom of the channelz44 inassembly. The plates 46 are placed imposition prior to mounting theblades inf the; disc periphery;

Referring particularly to Figure 8, the upstream ends of all the tunnels16 are blanked otfby blanking plates 47 which either co-operate with theroots:- of three blades or with the roots of four blades. Each blankingplate 47 has at its radially outer edge a short axial flange 48 toengage in undercut grooves in the platforms 12 of the blades with whichit co-operates, has apertures 49 therein which engage over hookedfeatures 50 projecting from the ends of the portions 15 between theblade slots and has tabs 51 at its radially inner edge which can beengaged in an axially-facing shallow channel 51a cut in the discperiphery. Those plates 47 which co-operate with four blade roots arepartly cut away adjacent their mid circumferential dimension so thatthey need only interlock with a pair of hooked features 50.

The blanking plates 30 for the downstream ends of the tunnels 16 whichare in communication with the passage extensions 17a, 18a may be formedas shown in Figure 7 or in any other convenient way. The downstream endsof the remaining tunnels 16, i.e. those into which passage extensions19a open, are uncovered.

In use pressure sealing air is fed to space 53 between the disc and thestationary structure 52 to prevent inward leakage of the working fluidat the upstream edges of the blade platforms 12, and it will thus beappreciated that since the space 40 bounded by the axial flange 41 isseparated from the working fluid passage of the turbine through twolabyrinth seals, and since the pressure between the labyrinth seals inmaintained high for sealing purposes, the pressure within this space 40can be maintained at an even higher value.

As in the previous construction the pressure air may be abstracted fromthe compressor of the gas-turbine engine.

I claim:

1. A bladed construction of the axial flow kind comprising a rotor discstructure, a plurality of blades, the blades having at their radiallyinner ends integral blade attachment portions; the blade attachmentportion of each blade element comprising a shouldered root-fixingportion engaging a corresponding shouldered slot in the rotor discwhereby the blade is retained in position on the rotor disc structure, ablade platform spaced radially from the root-fixing portion, the bladeextending from the platform, said blade platforms together forming asubstantially complete annular shroud, and a circumferentially-narrowaxially-extending stem joining said platform to said root-fixingportion, whereby in the assembly of said blades on the rotor discstructure axiallyextending spaces of substantial circumferentialdimensions are formed between the pairs of adjacent stems,

said axially-extending spaces forming duct passages; each blade havingat least a lengthwise inlet passage therein and a lengthwise deliverypassage therein, each blade having its inlet and delivery passagesinterconnected at their ends remote from the attachment portion of theblade, the inlet and delivery passages extending into the stem andopening through opposite sides thereof into the duct passages on eachside of the attachment portion respectively, and each blade beingarranged with its inlet passage opening into the same duct passage asthe inlet passage of the next adjacent blade on one side of it whereby acooling fluid supply to the blade and said adjacent blade on said oneside can be effected through said duct passage, and with its deliverypassage opening into the same duct passage as the delivery passage ofthe next adjacent blade on the other side of it whereby said latter ductpassage forms an exhaust passage for cooling fluid from said blade andfrom said next adjacent blade on the other side.

2: A Blades dense-nation as claimed in elaim 1; comprising also blankingmeans mounted onthe rotordisc structure and extending. over at: least;the corresponding ends of -alternate duct passages to. close. them. andover the opposite ends of the remaining duct passages to close theseopposite ends. v

3". A bladdjconstruction as claimed in claim 2, having the blankingmeans mounted on the-rotor disc structurew and; extending over the:ends: of: the-Iduetpassages into whichthe said inlet passages open-,1,to elose offthe ends of said duct passages on the downstream side of therotor disc structure, in combination with means supplying cooling fluidto the upstream side of the rotor disc structure.

4. A bladed construction as claimed in claim 1 comprising also blankingmeans mounted on the rotor disc structure and extending over the ends ofall the duct passages to one side of the rotor disc structure to closethem and on the opposite side of the rotor disc structure extending overthe ends of the duct passages in communication with the inlet passagesto close them, and means to supply cooling fluid to the duct passages incommunication with the inlet passages comprising a radially-extendingannular channel cut in the periphery of the rotor disc structure to opento each of the duct passages and blanking members located in the channelto prevent delivery of pressure fluid from the channel into those ductpassages into which the blade delivery passages open.

5. A bladed construction as claimed in claim 4, comprising an axialflange on the rotor disc structure, and fixed structure co-operatingwith said flange encircling a space, and drillings through the rotordisc structure from the space to the bottom of said channel.

6. A bladed construction of the axial flow kind comprising a rotor discstructure, a plurality of blades, the blades having at theirradially-inner ends integral blade attachment portions; the bladeattachment portion of each blade comprising a shouldered root-fixingportion engaging a correspondingly-shouldered slot in the rotor discwhereby the blade is retained in position on the rotor disc structure, ablade platform spaced radially from the root-fixing portion, the bladeextending from the platform, said blade platforms together forming asubstantially complete annular shroud, and a circumferentially-narrowaxially-extending stem joining said platform to said root-fixingportion, whereby in the assembly of said blades on the rotor discstructure axially-extending spaces of substantial circumferentialdimensions are formed between the pairs of adjacent stems to aflordaxially-extending duct passages; each blade having at least a lengthwiseinlet passage therein and a lengthwise delivery passage therein, eachblade having its inlet and delivery passages interconnected at theirends remote from the attachment portion of the blade, the inlet anddelivery passages extending into the stem and opening on opposite sidesthereof thereby to communicate with the duct passages on each side ofthe attachment portion respectively, and each blade being arranged withits inlet passage opening into the same duct passage as the inletpassage of the next adjacent blade on one side of it whereby a coolingfluid supply to the blade and to said next adjacent blade on said oneside can be eflected through said duct passage, and with its deliverypassage opening into the same duct passage as the delivery passage ofthe next adjacent blade on the other side of it whereby said latter ductpassage forms an exhaust passage for cooling fluid from said blade andfrom said next adjacent blade on said other side.

7. A bladed construction as claimed in claim 6, comprising also blankingmeans mounted on the rotor disc structure and extending over at leastthe corresponding ends of alternate duct passages to close them and exmewtending over the opposite ends of the remaining duct passages toclose them. I I

8. A bladed construction as claimed in claim 7, having the blankingmeans-mounted on the rotor disc structure and extending over the ductpassages into which the said inlet passages open, to close ofl? the endsof said duct passages on the downstream side of the rotor discstructure, in combination with means supplying cooling fluid to theupstream side of the rotor disc structure.

1 References Cited inthe file of this patent UNITED STATES PATENTS NoackJuly 10, 1934 Holzwarth Jan. 25, 1944 Schmitt Aug. 11, 1953 LedineggIan. 26, 1954 Bruckmann Jan. 29, 1957 FOREIGN PATENTS Great Britain Jan.17, 1947

